The present invention generally relates to a system and a method for providing an antenna and, more specifically, to a system and a method for providing a quasi-isotropic antenna.
In an increasingly mobile working environment, short-range communications standards were developed to help in eliminating wires and cables between stationary devices, mobile devices and/or combinations thereof. Examples of short-range communications standards include, for example, IEEE 802.11 and HyperLan. Another example of a short-range communications standard is the global standard called Bluetooth. Bluetooth is a relatively short-ranged wireless technology that has found application in ranges under approximately 100 yards and has proven popular in providing personal area networks (PANs) located in homes and small offices. Unlike other conventional wireless techniques such as infrared (e.g., IrDA), Bluetooth does not require a direct line of sight for communications. In addition, Bluetooth can provide, for example, point-to-point and/or point-to-multipoint connections in piconet and/or scattemet configurations.
Bluetooth generally includes hardware components, software and interoperability requirements. Bluetooth hardware includes a 2.4 GHz Bluetooth radio and provides spread spectrum techniques such as frequency hopping. For example, Bluetooth may operate in a 2.4 GHz to 2.48 GHz range in which signal hops may occur among 79 frequencies at 1 MHz intervals. Furthermore, at present, Bluetooth can support voice channels, for example, of 64 kb/s and asynchronous data channels of, for example, 723.2 kb/s asymmetric or 433.9 kb/s symmetric.
In theory, Bluetooth technology can be installed in handheld wireless communications devices such as, for example, cellular phones or personal digital assistants (PDAs). For example, a Bluetooth antenna can be mounted on a handheld device in addition to the cellular antenna. However, in general, Bluetooth technology tends to interfere with the cellular transceivers including cellular antennas. Furthermore, the converse is true that cellular transceivers including cellular antennas tend to interfere with Bluetooth technology. Accordingly, neither the Bluetooth antenna nor the cellular antenna works effectively.
In another conventional device, a Bluetooth patch antenna is placed on the back of the cellular phone with additional shielding between the Bluetooth antenna and the back of the cellular phone. However, such an arrangement suffers if, for example, the cellular phone is disposed on its back on a table, then the Bluetooth antenna is blocked by the shielding and the table from effective Bluetooth communications.
The consequences become exacerbated in situations in which the Bluetooth technology is used for automated communications in which the user and/or the local wireless network may rely. For example, the Bluetooth technology may be configured to transfer e-mail messages from a local wireless network in an office to the cellular/Bluetooth handheld device carried by the user when the user is in range (e.g., in the office) of the local wireless network. If the user places the handheld device in such an orientation as to effectively shield the Bluetooth antenna from the local wireless network (despite being in range of the local wireless network), then the e-mail messages will not be transferred to the handheld device, the user will be unaware of communications problems and the user will assume that he or she had no unread e-mail messages on the local wireless network.
The present invention alleviates to a great extent the disadvantages of conventional apparatus and methods for wireless communications.
In a preferred embodiment, the present invention provides a system and a method for wireless communications including a wireless communications device. The wireless communications device includes a microstrip that has been structured to transmit and to receive wirelessly a short-range wireless communications signal. The microstrip may use any conducting material present on the printed wiring board. This material may form, for example, power lines and/or any other signal lines that form a part of the wireless device""s electrical circuitry.
The present invention has an advantage by using existing shielding to provide isolation between the existing antenna and the microstrip which has been adapted to be a short-range antenna.
The present invention also has an advantage in that the meandering line shape of the microstrip provides an antenna with quasi-isotropic radiation characteristics. Such quasi-isotropic radiation characteristics are further enhanced in configurations in which the micro strip is disposed on the front side and the rear side of a printed circuit board of the wireless communications device.
The present invention further has an advantage in that, for short-range communications, an additional antenna and/or additional shielding need not be added to an already crowded circuit board of the wireless communications device.
These and other features and advantages of the present invention will be appreciated from review of the following detailed description of the present invention, along with the accompanying figures in which like reference numerals refer to like parts throughout.